Herbimycin A inhibits BCG- and SP-A-BCG killing by rat bone marrow macrophages. RBMM were incubated with BCG or SP-A-BCG (B/S) complexes as described in Figure 1. After removal of unbound BCG, cells plus ingested organisms were supplied with fresh medium minus antibiotics, plus serum containing 2 μCi per well of 3H-uracil. After five days incubation, macrophages were lysed with SDS, and viable BCG were collected by filtration over GF/C filters. The filters were dried, and then counted by liquid scintillation counting. Viability of macrophages in companion wells was verified by vital dye exclusion. Results shown are the average of quadruplicate determinations ± S.D., and are representative of two separate experiments. * = p < .001 for BCG compared to SP-A/BCG; ** = p < .001 for SP-A/BCG + NMMA compared to BCG and SP-A/BCG.